This Python program reads a list of prime numbers from a file, and then finds pairs of primes whose last digits (when considered as strings) multiply to a certain target. This Python program reads a list of prime numbers from a file, and then finds pairs of primes whose last digits (when considered as strings) multiply to a certain target.
The program consists of two main functions:
-
read_primes_from_file(filename)
: This function reads a list of prime numbers from a file. The file should contain one prime number per line. -
find_prime_pairs(target_last_digit, primes)
: This function finds pairs of primes whose last digits multiply to a certain target. The primes are considered as strings, and the last digit of each prime is extracted for the multiplication.
The program reads the primes from a file, finds the pairs of primes, and then prints these pairs.
The program can be modified to consider more than one digit at the end of each prime. To do this, you would need to change the line in find_prime_pairs
that extracts the last digit:
last_digit1 = int(str(primes[i])[-1:])
last_digit2 = int(str(primes[j])[-1:])
You can change -1:
to -n:
to consider the last n
digits, where n
is the number of digits you want to consider.
The program prints the pairs of primes that it finds. If you want to output a full list of the primes that it read from the file before it attempts to find the pairs, you can add the following line after reading the primes:
print(primes)
This will print the list of primes.